1. Field
The following description relates to a system for wideband IP telephony services through an Internet Set-Top Box (ISTB) and, more particularly, to a system for implementing wideband voice communication services using a wideband voice codec through an ISTB, for controlling Real-Time Transport Protocol (RTP) packet payload to process a variety of wideband speech frame payloads, and for controlling a jitter buffer to maintain conference call synchronization.
2. Description of the Related Art
An Internet Set-Top Box (ISTB) has been developed to provide a variety of add-on services as well as broadcast services for digital televisions. An example of the add-on service is IP telephony, which is based on a narrowband codec, such as G.711 or G.729 audio codec. The narrowband codec, such as G.711 or G.729 audio codec, samples across a frequency range from about 300 Hz to 3.4 kHz and provides audio quality comparable to a typical analog telephone.
In order to provide better quality and more flexibility than the narrowband codec, a wideband codec, such as G.711.1 or G.729.1, which samples across a frequency range from about 50 Hz to 7 kHz has been designed.
In the case of the wideband codec, a transmission bit rate of a voice codec frame may be changed depending on network conditions during a telephone call. However, there has not been provided a technology for processing a variety of speech frame payloads which are included in Real-Time Transport Protocol (RTP) packet payloads.
Further, in the case of a conference call service through the ISTB, there has not been provided a technology for maintaining call synchronization for users participating in the conference call service to use conference services according to a local network for their IP phones and the ISTB.